News that Usama Hasan – an imam at Masjid al-Tawhid in Leyton, east London, and contributor to Comment is free – has deemed it necessary to retract some of his statements supporting the theory of evolution following a campaign of intimidation against him by opponents, some of whom described him as being an "apostate", should be of concern to all who hope for more open debate and discussion in Britain's Muslim communities.

Five years ago, I wrote on Comment is free about the widespread lack of understanding and appreciation of Darwin's theory of evolution among many UK Muslims. I said:

"If its encounter with evolution is not to turn out to be Islam's Galileo moment then Muslim scientists have a crucial responsibility to engage in frank discussion about it with students and with religious scholars in an open and honest manner to help address a dogmatic aloofness which can only harm future Muslim science students."

This ignorance and dogmatism about evolution is not simply limited to the Harun Yahya creationists – who, incidentally, began a UK tour on Monday and whose leader I debated with here on Comment is free a few years back. Nor is it limited to the Saudi clerics, who frequently visit Masjid al-Tawhid. Nuh Ha Mim Keller, for example, is a popular American Sufi teacher now based in Jordan. Responding to a question from a student of his about evolution, Keller maintained that evolution did not even qualify to be described as a scientific theory because it is:

"… not in principle falsifiable, though the possibility that some kind of evidence or another should be able in principle to disprove a theory is a condition (if we can believe logicians like Karl Popper) for it to be considered scientific. By its nature, fossil evidence of intermediate forms that could prove or disprove the theory remained unfound and unfindable. When I read this, it was not clear to me how such a theory could be called 'scientific'."

Now this is just utter bunkum. If Keller or his followers are able to find, say, some mammalian fossils cropping up in rocks dating back to the Cambrian period, that would pretty much falsify Darwin's theory. The point is, after 150 years of trying, no one has yet produced any evidence to knock down Darwin's theory and it has proven itself to be an extremely powerful framework for helping us to better understand our world and the relationship between all organisms residing therein.

So, it was welcome news when Hasan wrote on Comment is free in 2008 in support of Darwin's theory and pointed out there were Muslim scholars including the 10th-century Persian philosopher Ibn Miskawayh who had supported a very similar theory to that of Darwin. Hasan has also gone on to make the seemingly rather sensible point that Islamic scholars who lack training in the biological sciences should refrain from confidently declaring supporters of Darwin's theory to be wrong.

Nevertheless, since his 2008 article, Hasan has faced increasingly vocal criticism from some Muslims who believe his views on evolution fundamentally contradict Islamic teachings about the creation of Adam and therefore make him unfit to hold the position of imam. This opposition gained momentum in recent weeks following the intervention of a visiting Saudi cleric, who apparently said that Muslims should not pray behind an imam if the latter was a supporter of evolutionary theory. Hasan tried to directly address his critics by delivering a lecture on "Islam and evolution" at Masjid al-Tawhid in January 2011, but the lecture was disrupted by his opponents who became heated when Hasan asserted his belief that Adam was descended from human-like ancestors.

Hasan's subsequent contention on his blog on 15 February that his detractors had only "added weight to Darwin's theory by behaving like a bunch of baboons" may perhaps not have served to reduce the temperature surrounding the controversy.

Finally, last Friday, following a continuing vitriolic online campaign against him, Hasan appeared to relent and issued a "clarification and retraction" on his blog stating that "I regret and retract some of my statements in the past about the theory of evolution" and "I do not believe that Adam, peace be upon him, had parents".

Given the pressure he was under – and the police are said to have recently warned him about his personal safety – it is understandable why Hasan has chosen to retract some of his past statements. However, this episode reflects badly on the current state of Muslim intellectual life. It is a dismal state of affairs when an imam and Muslim scholar is not allowed to argue that there may be more than one permissible interpretation of the traditional story of Adam. And how ironic that many religious scholars still feel qualified to comment authoritatively on evolution despite not having studied anything about it when the very first commandment of the Qur'an was to "Read!".

This is not to say that scriptural literalism is a problem only in some Muslim communities. Darwin's theory has still to be embraced by a number of large evangelical congregations in the US, who seem certain in their belief that the Earth is only 6,000 years old and that the fossils we possess are just remnants of those that perished in Noah's flood.

Furthermore, opposition to Hasan has been building due to a number of other factors, too, not just his support for evolutionary theory. In particular, his role as an official adviser to the government-funded Quilliam Foundation – a body widely viewed with contempt by many British Muslims – and his recent trip to Afghanistan on a Foreign Office junket have unsettled many of his hitherto supporters who are deeply uncomfortable with the UK's continuing involvement in the war there.

In my view, though, the controversy at Masjid al-Tawhid does highlight a fundamental problem. Muslims are rightly taught to respect ulama ("people of knowledge"). In practice, however, those regarded and treated as ulama are only those who have spent years studying ancient books in Arabic in traditional Islamic seminaries.

On a visit to Sudan some years back I recall the Sudanese Islamic scholar Hasan al-Turabi saying that Muslims needed to expand their definition of who qualified to be an alim ("scholar", singular of ulama) and said that doctors should be viewed as being the ulama in the medical field, engineers in the engineering field and so on. The question of human evolution is undoubtedly a scientific one and it makes little sense to go to a religious scholar who lacks scientific training and hope to get a sound answer.

Which brings me back to the point I made in 2006 about the responsibility of Muslim scientists. Since 2006 we have seen the setting up of new websites by Muslim scientists to more openly discuss evolution and its implications for some traditional interpretations of religion. This can only be good news, especially for those who are worried that some mosques are no longer fulfilling their role as community hubs and centres for debate and discussion.